Simple & Compound Int.- Groups - Rates - Ratios Flashcards
Compound Interest: Semiannual
Divide interest rate in half and apply it every 6 months
Compound Interest: Semiannual
Divide interest rate in half and apply it every 6 months
Compound Interest: Quarterly
Divide interest rate into 4s and apply every 3 months (every three months is 4 times within a year since 12/3 = 4)
Group Formula (and when to use…)
Group problems when you see the words “both or neither”
When you see words like: “both or neither”
Total = g1 + g2 - B + N
g1 = group 1 g2 = group 2 B = both N = neither
Group grid (and when to use…)
When you see worlds like: “either and or”
Percent change
Percent change when question about
- percent increase
- percent decrease
Percent change = (difference / original) * 100
Percent increase: smaller number is the original value
Percent decrease: larger number is the original value
Phrases: Percent more Percent less Percent increase Percent decrease
Ratio
If you see the word ratio on the GRE, check to see if it is asking about the total. If the question is asking about the total, you can solve it like you solve ratio questions. If it is not asking about the total you can set up a proportion
Rate Pie
/ distance/ work /
time * rate
think “D T R”
Average Pie
How do you know how many times to use an average pie?
/ total /
# of things * average
Typically, however many times you see the word “average” in the question is how many average pies you do
“of” when translating percent’s
multiply *
“percent” when translating percent’s
divide by 100
“what” when translating percent’s
variable (x)
“is” / “are” / “were” when translating percent’s
equals =
.80% is equal to what over 100?
.80/100
If you don’t use 100 in a percent example what do you have to do at the end of the problem?
You have to convert it back to a percent which in most cases means you have to multiply it by 100
profit = ?
profit = sale price - cost
“regular” shape
a shape where all the sides and angles within the shape are all the same
formula for knowing the degree of angles within a geometric shape
180(n - 2) where n = the number of sides of the shape.
for example, to solve for a “regular” pentagon you would do 180(5 - 2)
When you do what the test writers expect, you don’t get the best score possible!!
do the unexpected!! don’t be predictable
0 is even or odd?
even!
Divisibility Rules: 2
A number is divisible by 2 if its units digit is even
Divisibility rules: 3
sum of digits divisible by 3
On January 1, 2015, the balance of an account that pays simple annual interest of 2% is $3, 750. How much money will be in the account on January 1, 2020?
$4,125
Val opens a CD with an initial deposit, if the account earns 4% annual interest and no other transactions are made, then what percent of the initial deposit will be paid in interest after two years?
8%
